Patterned Orientations of Liquid Crystals on Affinity Microcontact Printed Proteins

Abstract

ELX-02C ellipsometer with a 632.8 nm laser at a 70 angle of incidence. AFM images were obtained with a Digital Instruments Nanoscope III in tapping mode. Optical images were obtained with a Nikon Eclipse ME600L microscope using the DN100 image capture system.Fabrication of Polymer Objects: Gold substrates were patterned by microcontact printing of thiol initiator using a PDMS stamp and ªbackfillingº by immersion in a 5 mM ethanolic solution of undecanethiol for 30 s. Polymer brushes of poly(glycidyl methacrylate) (PGMA) were grown from these substrates using CuCl/CuBr 2 catalyzed ATRP, as published previously [9]. Polymer layers were crosslinked by immersion of the substrates in 2 M methanolic NaOH at 60 C for 25 min, washed with water and methanol, and dried under a nitrogen stream. For fluorescence microscopy, samples were dyed by immersion in a dry dichloromethane solution containing 5 mg mL Patterned Orientations of Liquid Crystals on Affinity MicrocontactPrinted Proteins** By Matthew L. Tingey, Edward J. Snodgrass, and Nicholas L. Abbott* In the 11 years since Whitesides and co-workers demonstrated microcontact printing to be a broadly useful method for patterning surfaces with organized monolayers of alkanethiols, [1,2] this method and other closely related ªsoft lithographicº techniques [3] have been extended to the patterning of colloids, [4] metal complexes, [5] polymers, [6,7] proteins, [5,8] and metal ions. [9] In its simplest form, microcontact printing comprises the ªinkingº of the surface of a poly(dimethylsiloxane) (PDMS) stamp with a solution of the species to be patterned, and conformal contact of the inked stamp with a second surface. Appropriate engineering of the physicochemical properties of the surface of the stamp and the second surface leads to the transfer of the inked species from the stamp to the second surface. For example, proteins adsorbed to the surface of a stamp will be transferred to a second surface when the second surface possesses a surface energy that is higher than that of PDMS. [10] This method permits the patterning of proteins on surfaces and has been exploited to prepare surfaces for biomolecular assays and patterned cell culture.[11]

Chemical and biological sensing using liquid crystals

“…This point is illustrated in this section by describing LC ordering on surfaces presenting oligopeptides. Here we also note that, although LCs can report proteins on surfaces, the complexity of proteins has hindered identification of the intermolecular forces acting between the proteins and LCs [42, 50]. The simpler structure of oligopeptides as compared to full proteins, as well as the ability to make systematic modifications to oligopeptide structure and stereochemistry has led to fundamental insight into the intermolecular interactions underlying the ordering of LCs at biomolecular interfaces [42].…”

Optical detection of deoxyribonucleic acid hybridization using an anchoring transition of liquid crystal alignment

“…11 Moreover, the long-range orientational order and large optical anisotropy of the LC can transform various surface events into amplified optical signals that can be easily observed without expensive detection systems. 7,9,10 In this letter, we propose a novel method for detecting hybridization results in a DNA chip using an anchoring transition of LC alignment. To investigate the effects of structural changes of DNA on the LC alignment, we used a functional substrate on which single-stranded oligonucleotide DNA ͑ssDNA͒ was immobilized to the surface.…”

Influence of 4-cyano-4′-biphenylcarboxylic acid on the orientational ordering of cyanobiphenyl liquid crystals at chemically functionalized surfaces

“…On areas of the surface presenting microcontact printed proteins (squares), the orientation of the pure 5CB was parallel to the surface (planar) with a preferred azimuthal orientation. We have previously reported that the azimuthal orientation of liquid crystals on microcontact printed proteins closely follows the azimuthal direction of contact between the stamp and the surface [16]. On the regions of the ammonium-terminated monolayer that did not support anti-biotin IgG (between squares), the 5CB became bright when the sample was rotated by an angle of 45 • .…”

“…Chemically functionalized surfaces provide access to a wide range of interfacial properties through the introduction of interactions that involve hydrogen bonding [1][2][3][4][5], electrical double of this phenomenon for the creation of chemical and biological sensors based on liquid crystals [16,[25][26][27][28][29]. Although it is well established that the ordering of liquid crystals is sensitive to the molecular-level structure of interfaces [30], the types of chemically functionalized surfaces and liquid crystals that are relevant to the creation of chemical and biological sensors differ from those typically studied in the past in the context of creating electro-optical technologies such as liquid crystal displays (e.g., surfaces prepared from polyimides).…”